To be able to introduce daylight into a building has in all times been of great interest. The human being has during the years, apart from the modern era with electrical light, been dependent on the daylight and has biologically evolved under this constraint. The changing intensity and colour of the daylight has a significant effect on peoples perception of passed time, when to have different types of meals, when to sleep and when to get up, just to mention a few.
When designing buildings the introduction of daylight is a major design consideration. Different kind of windows and skylights are the most common technology used. They are limited when it comes to transporting daylight into buildings; only areas close to the windows or skylights are illuminated. They are also taking up a lot of space on the building's exterior; this is especially a problem on the roofs where space is needed also for other things such as ventilation fans and antennas.
A few sun collectors for illumination purposes are available today; they are all bulky and difficult to integrate in the architecture. Many of them also have moveable parts exposed to weather and wind which increases the risk for malfunction.